18 accepted papers
Visual servoing provides the flexibility of robot control in dynamic environments, but three-dimensional (3-D) robot visual servoing is challenging due to the 2-D nature of the image space. Adaptive homography-based visual servoing (HBVS) is effective for 3-D robot pose control under various paramet
We propose PRED-MPPI, the first MPPI variant that seamlessly integrates real-time disturbance preview and adaptive discretization for quadrotor tracking control under significant model inaccuracies and time-varying disturbances. Unlike prior MPPI variants (e.g., mathcal{L}_1-MPPI, DA-MPPI), which as…
SP-based synthesis yields two-time-scale control that allows compliant-joint robots to achieve high-quality tracking at low implementation cost. Composite learning enables exact online identification and control of robots without the stringent condition known as persistent excitation (PE). However, …
Controlling articulated soft robots (ASRs) driven by variable stiffness actuators (VSAs) is challenging because they are highly nonlinear and difficult to model accurately. This paper proposes an efficient neural network (NN) learning control solution for ASRs driven by agonistic-antagonistic (AA)-V
Articulated soft robots (ASRs) driven by variable stiffness actuators (VSAs) are challenging to control well due to their highly nonlinear dynamics and difficulties in accurate modeling. The paper proposes a locally weighted learning (LWL)-based robust composite learning control (RCLC) solution for
Ensuring safety is crucial to promote the application of robot manipulators in open workspaces. Factors such as sensor errors or unpredictable collisions make the environment full of uncertainties. In this work, we investigate these potential safety challenges on redundant robot manipulators, and pr
This paper presents the development of a multiple-input multiple-output (MIMO) coupling controller for the independent-setup variable stiffness actuator (VSA). The dynamic model of the independent-setup VSA is typically considered decoupled due to the slight coupling between the joint and stiffness
To enhance robustness against noise resulting from velocity measurement and acceleration estimation in robot online identification and adaptive control, the robot dynamics should be filtered and parameterized to generate a filtered regression matrix regarding identifiable parameters. However, genera
This paper proposes a task-oriented model predictive control (ToMPC) framework for safe and efficient robotic manipulation in open workspaces. The framework unifies collision-free motion and robot-environment interaction to address diverse scenarios. Additionally, it introduces task-oriented obstacl
The ability to handle contact makes robots qualified for many complicated tasks, such as welding, hammering, and wiping. Robot cameras facilitate position planning and control without the geometric knowledge of contact surfaces since they can project contact surfaces onto a 2-dimensional image plane…
Variable stiffness actuators (VSAs) are an important class of compliant actuators that can benefit the robustness and task adaptability of robotic systems. However, controlling VSAs is still challenging as VSAs are difficult to model exactly and have highly nonlinear characteristics. This study appl
Variable impedance control (VIC) is paramount for robots to improve safety and effectiveness in physical human-robot interaction. However, achieving variable target impedance with guaranteed stability is not trivial, particularly under parametric uncertainty in the robot dynamics. This letter propos
Parameter convergence in adaptive control is crucial for improving the stability and robustness of robotic systems. Nevertheless, a stringent condition named persistent excitation (PE) needs to be satisfied to ensure parameter convergence in the conventional adaptive robot control. Composite learnin…
To achieve high-accuracy manipulation in the presence of unknown disturbances, we propose two novel efficient and robust motion control schemes for high-dimensional robot manipulators. Both controllers incorporate an unknown system dynamics estimator (USDE) to estimate disturbances without requiring…
This paper presents a conceptual magnetically anchored and guided flexible endoscope for minimally invasive surgery (MIS). Leveraging both the magnetic coupling between the external and internal permanent magnets and the bending of a flexible joint, the endoscope offers improved maneuver-ability and…
Zeroing neural networks (ZNNs) are powerful alternatives to solving quadratic programming (QP) for constrained control of parallel and serial robots. A recent study showed that a ZNN solver designed based on a perturbed Fischer-Burmeister function (pFB-ZNN) achieves more satisfactory performance tha…
Obstacle avoidance (OA) and joint-limit avoidance (JLA) are essential for redundant manipulators to ensure safe and reliable robotic operations. One solution to OA and JLA is to incorporate the involved constraints into a quadratic programming (QP), by solving which OA and JLA can be achieved. There…
Series elastic actuators (SEAs) are known to offer a number of advantages such as high force/torque fidelity, low impedance, and tolerance to shocks, which make it suitable for the applications involving human-robot interaction. In existing SEA-driven robot systems, the control objective is usually